bazaarflux/src/main/java/me/lethunderhawk/world/util/schematic/SchematicPlacer.java

package me.lethunderhawk.world.util.schematic;

import com.google.gson.Gson;
import com.google.gson.JsonParseException;
import com.sk89q.worldedit.EditSession;
import com.sk89q.worldedit.WorldEdit;
import com.sk89q.worldedit.bukkit.BukkitAdapter;
import com.sk89q.worldedit.extent.clipboard.Clipboard;
import com.sk89q.worldedit.extent.clipboard.io.ClipboardFormat;
import com.sk89q.worldedit.extent.clipboard.io.ClipboardFormats;
import com.sk89q.worldedit.extent.clipboard.io.ClipboardReader;
import com.sk89q.worldedit.function.operation.Operation;
import com.sk89q.worldedit.function.operation.Operations;
import com.sk89q.worldedit.math.BlockVector3;
import com.sk89q.worldedit.session.ClipboardHolder;
import org.bukkit.Location;
import org.bukkit.World;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;

public final class SchematicPlacer {

    private static final Gson GSON = new Gson();

    private SchematicPlacer() {}

    /**
     * Places a schematic at a world location.
     *
     * @param schematicFile .schem file
     * @param world target world
     * @param anchor world-space anchor
     * @param rotation rotation to apply
     * @return true if placed successfully
     */
    public static boolean place(
            File schematicFile,
            World world,
            Location anchor,
            Rotation rotation
    ) {
        if (!isValidSchematic(schematicFile)) return false;

        SchematicMetadata metadata = loadMetadata(schematicFile);
        Clipboard clipboard = loadClipboard(schematicFile);

        if (clipboard == null) return false;

        if (metadata != null) {
//            BoundingBox box = metadata
//                    .boundingBox()
//                    .shift(anchor.toVector());

            // Optional validation
            // if (!isAreaClear(world, box)) return false;
        }

        Vector3i schematicAnchor =
                metadata != null ? metadata.anchor() : new Vector3i(0,0,0);

        return paste(
                clipboard,
                world,
                anchor,
                schematicAnchor,
                rotation
        );
    }

    // ----------------------------------------------------------------

    private static boolean isValidSchematic(File file) {
        return file != null && file.exists() && file.getName().endsWith(".schem");
    }

    private static Clipboard loadClipboard(File file) {
        ClipboardFormat format = ClipboardFormats.findByPath(file.toPath());
        if (format == null) return null;

        try (ClipboardReader reader =
                     format.getReader(new FileInputStream(file))) {
            return reader.read();
        } catch (IOException e) {
            return null;
        }
    }

    private static SchematicMetadata loadMetadata(File schematic) {
        File meta = new File(
                schematic.getParent(),
                schematic.getName().replace(".schem", ".json")
        );

        if (!meta.exists()) return null;

        try (FileReader reader = new FileReader(meta)) {
            return GSON.fromJson(reader, SchematicMetadata.class);
        } catch (IOException | JsonParseException e) {
            return null;
        }
    }

    private static boolean paste(
            Clipboard clipboard,
            World world,
            Location anchor,
            Vector3i schematicAnchor,
            Rotation rotation
    ) {
        com.sk89q.worldedit.world.World weWorld =
                BukkitAdapter.adapt(world);

        BlockVector3 target = BlockVector3.at(
                anchor.getBlockX() - schematicAnchor.x(),
                anchor.getBlockY() - schematicAnchor.y(),
                anchor.getBlockZ() - schematicAnchor.z()
        );

        try (EditSession session = WorldEdit.getInstance()
                .newEditSessionBuilder()
                .world(weWorld)
                .build()) {

            ClipboardHolder holder = new ClipboardHolder(clipboard);
            holder.setTransform(
                    holder.getTransform().combine(rotation.toTransform())
            );

            Operation operation = holder
                    .createPaste(session)
                    .to(target)
                    .ignoreAirBlocks(true)
                    .build();

            Operations.complete(operation);
            return true;

        } catch (Exception e) {
            return false;
        }
    }
}